As disclosed in Patent Document 1 (Japan Patent No. 4941796), for example, a water conduit for spouting flush water supplied from a reservoir tank to the bowl portion is formed at the rear top portion of the toilet main body, and a rim portion is formed along the top edge portion of the bowl portion above this water conduit. In this rim portion, the radius of the inside corner portion formed on the inside of the toilet main body and the radius of the outside corner portion formed on the outside of the toilet main body are formed to have approximately the same size, and can be extremely small radii.